A Synergy between Controlled Salinity Brine and Biosurfactant Flooding for Improved Oil Recovery: An Experimental Investigation Based on Zeta Potential and Interfacial Tension Measurements

Figure 5

Zeta potential of single- and multiphase systems measured in this work. Single-phase value corresponds to the zeta potential measured in the rock samples saturated with FMB (Sw=1); FMB corresponds to the zeta potential measured at the end of the secondary FMB waterflooding when the rock sample was saturated with formation brine and residual oil (Sor=0.32); CSB corresponds to the zeta potential measured at the end of CSB flooding when the rock sample was saturated with CSB and residual oil (Sor=0.23); CSBS-R corresponds to the zeta potential measured at the end of CSB combined with 1 wt.% rhamnolipid waterflooding when the rock sample was saturated with CSBS-R and residual oil (Sor=0.19); CSBS-G corresponds to the zeta potential measured at the end of CSB combined with 1 wt.% greenzyme waterflooding when the rock sample was saturated with CSB-R and residual oil (Sor=0.17). The error bars reflect the accuracy of the instrument, noise level in measured voltage, and repeatability of results.